Prior Art
The present invention relates to the interferometric capture of measurement points on a region of an eye.
Corresponding methods and apparatuses are known in ophthalmology. Typically, an interferometer is used to carry out such examinations of the eye. By way of example, OCT (optical coherence tomography) scanners are used as interferometers; these scan the eye at discrete positions in the lateral direction and, in the process, capture stray-light profiles (axial profiles) of the eye along the optical beam. On account of the axial profiles, it is possible to define three-dimensional measurement points in the eye, which preferably represent one or more optical surfaces.
By way of example, Zeiss (U.S. Pat. No. 9,101,294 B2) discloses a method for processing data from an OCT device, wherein an increase in the precision of the calculation of ocular measurements is intended to be achieved by different approaches. The methods comprise novel scanning patterns, the use of techniques for determining the transversal eye movement and an improved algorithm for eye movement correction.
In particular, the method comprises capturing a first small set of data by means of OCT and using the data to model the cornea. The model is subsequently used to create a precise, movement-corrected model during a further measurement with a more dense number of measurement points.
Further, Duke (U.S. Pat. No. 8,403,481 B2) discloses a method for reducing movement artifacts in OCT measurements. In the method, data are ascertained using a scanning pattern, said data being distributed in such a way that at least certain spatially adjacent data points were not ascertained in sequence. To this end, use can be made of a scanning pattern in which spatially adjacent data points are ascertained in non-sequential fashion. By way of example, the sample may be scanned by a number of series of scanning lines, with some of the scanning lines lying between previously measured scanning lines.
Essential requirements of the measurement, particularly when measuring the eye, are, firstly, a short overall duration of the measurement and a high resolution, i.e. a large coverage of the area to be measured. The short overall duration is an essential criterion, in particular on account of the unavoidable movements of the eye during the measurement.
The known methods are disadvantageous in that the measurements take a relatively long time. On account of the relatively long measurement duration, there is an increased risk of the measurement results being influenced by eye movements of the patient, as a result of which only inaccurate measurement results are able to be obtained.